GUI: Full Title + version requires at least 748px wide window

[mikrosk]

I have noticed this shortly after the 2.8.0 release.

Atari backend uses 640x480 screen for the launcher which never allows to show the version properly. Experimenting with the OpenGL backend I have found the value 748px, anything narrower will start shrinking the title with "..." even if there is plenty of space.

See the attached screenshots.

[criezy]

In a66c497:

GUI: Fix display of version in classic theme

This fixes bug #14774.
This is a regression from commit 3857f71 that added the help button
to the classic layout. Instead of having the version text widget take
the full width, it added a horizontal layout, with the help button,
the version widget, and a space with the same width as the help button
(to keep the version centered I assume). But it also added two
additional spaces either side of the version text widget with no
specified width for no apparent reason. As a result the version widget
was only taking 1/3rd of the available space. This commit removes
those two spaces. It also changes the variable used to specify the
width of the space on the right to use the same variable that specifies
the width of the help button on the left. This clarifies that this
space is here for centering.

[criezy]

The issue only happens with the classic theme, and this is a regression from 3857f71 (thus present in releases since version 2.8.0).

That commit added the help button to the classic layout. Before the commit the version text widget was taking the full width of the window. The commit added a horizontal layout, with the help button on the left, the version text widget in the middle, and a space with the same width as the help button on the right (I am assuming for the purpose of keeping the version text centred). But it also added two additional spaces either side of the version text widget in the layout with no specified width. As a result the version widget was only taking 1/3rd of the available space. I cannot see any good reason for the presence of those additional spaces so I removed them in commit a66c497.